The present invention relates to an inflatable vault having a flexible multilobed double wall, in which only the air space situated between the two walls is pressurized, the area covered by it remaining at ambient pressure. Amongst other aims, this vault is designed to be opened out by simple inflation, and also to be collapsed by deflation, thus making it possible to alternatively cover an area during bad weather and uncover it during good weather.
A vault of this kind can be used for the temporary covering of large installations, such as stadiums having stands intended for spectators. In this case, the vault constitutes an enormous amount of fabric, weighing from fifty to one hundred tons, which is impossible to assemble in the factory, transport and install as a single completely finished unit. Alternatively, if the vault is composed of a plurality of elements, it is advisable that these elements be completely finished and tested at the factory, particularly for the purpose of checking their airtightness. However, it is also desirable that these elements be easily and quickly assembled together, without requiring expensive equipment at the site.
Vaults of this type, which can be opened out and collapsed by simple inflation and deflation and in which only the space between the two walls is pressurized, are already known. Examples of such vaults are in French Pat. Nos. 2,166,397 and 2,326,544.
French Pat. No. 2,166,397 relates to an inflatable structure comprising a series of inflatable boxes which bear against one another when they are inflated, and which are placed between two sheets, to which they are fixed and which are tensioned by the boxes when the structure is inflated. Because of the design of this structure, it cannot be used for constructions of large dimensions. Such use is one of the objects of the present invention.
French Pat. No. 2,326,544 relates to a flexible inflatable structure consisting of a bay which has at least two walls, is adapted to be opened out and folded up or collapsed, and is composed of a succession of contiguous, flattenable, pressurizable chambers whose dividing walls brace the outer, inner and sometimes middle wall of the bay. The numerous elements of which the vault is composed are simple elementary panels of leaktight fabric, which have to be joined on the site to make continuous joints which are both resistant and leaktight over great lengths. The assembly of these panels requires very accurate manufacturing tolerances and also considerable, delicate assembly work on the site. Thus, there is no assurance that the resulting product will be completely reliable.
Moreover, these two documents do not describe an inflation means for enabling an enormous amount of air to be blown in under light pressure between the two walls. Such inflation means is necessary in order to open out a vault of large dimensions within a period of time sufficiently short to be of practical interest.